The present invention relates to data storage apparatus for storing data on a tape medium. More particularly the present invention relates to the storage of tape-usage information in the system-log areas of multi-partition tapes.
The use of a system log area to record tape-usage information on a storage tape is well-known (see, for example, the document "DAT DATA Storage Format Description," Revision A.00, dated February 1988 and generally available as of that date from Hewlett-Packard Limited, Bristol, England).
A multi-partition tape is one in which data is independently recorded in two or more sections (Partitions) of the tape, the data being recorded in each section according to the same predetermined format. Such a multi-partition tape forms the subject of our co-pending U.S. Pat. Application Ser. No. 07/442,545, filed Nov. 28, 1989.
The application of the concept of a system log area to multi-partition tapes is referred to in the aforesaid United States patent application and is described more fully in the document Digital Data Storage Format Description" dated October, 1988 and generally available as of December 1988 from Hewlett-Packard Limited, Bristol, England. More particularly, data storage apparatus is envisaged of the general form comprising:
recording means for recording data on a tape medium in accordance with a predetermined format, the format specifying a plurality of tape recording sections arranged one after another along the tape medium and including a log area for storing tape usage information and a data area for storing the data, and PA1 control means operative to cause the recording means to record data in at least two different longitudinally-spaced sections of the tape medium with data recordal in each section being respectively effected in accordance with the format,
the recording means including a tape-usage monitor operative to accumulate tape-usage information relating to data recordal on the tape medium, the form of the accumulated tape usage information being such as to enable tape-usage information relating to each said tape section to be derived therefrom, the recording means being operative to record the accumulated tape-usage information in the said log areas associated with the said tape sections. In the arrangement disclosed in the aforesaid format Description, the tape usage information recorded in the log area of each tape section (Partition) relates solely to data recordal in that section.
Although both the aforesaid United States patent Application and Format Description describe format implementations specifically intended for helical scan recording techniques, the general principles disclosed regarding the use of system log areas in multi-partition tapes apply also where other recording techniques are employed.